There is a growing awareness of the environmental and public health implications of mycotoxins, and their potential for toxic interaction and synergy in combination. A variety of toxicological effects in animals have been attributed to mycotoxins. Embryonic death, inhibition of fetal development, and abortions have been attributed to aflatoxins and zearalenone as well as, the ergot toxins and rubratoxin. Teratogenicity has been described for aflatoxins, ochratoxin, T-2 toxin, zearalenone, sterigmatocystin, and rubratoxin. However, the effects of naturally occurring mycotoxins in combination are not well defined. Consequently, the ability to rapidly and accurately detect and rank teratogenic mycotoxins in vitro (according to priority for further testing) is a critical need. In this project, target mycotoxins and/or mixtures will be evaluated for their teratogenic potency via exposure to extracorporeally maintained, postimplantation rat embryos (explanted at day 10 of gestation and cultured in the presence of test mycotoxins for 45 hours). Embryonic differentiation, morphology, DNA and protein content of mycotoxin-exposed embryos will be scored during the early stages of organogenesis and recorded. In the final phase of the project, target mycotoxins and mixtures identified in vitro (by embryo assay) as potent teratogens will be characterized in vivo employing the Sprague-Dawley rat as a sensitive model. In addition this project will provide opportunities for graduate students to study developmental toxicological in the masters degree program. It will also provide an excellent base to expose undergraduates to research techniques that they can use while pursuing biomedical degrees.